Re: [PATCH v2 2/4] dmaengine: rcar-dmac: Add for_each_rcar_dmac_chan() helper

Laurent Pinchart
2021-01-26T23:02:03Z

Hi Geert,

Thank you for the patch.

On Mon, Jan 25, 2021 at 03:24:29PM +0100, Geert Uytterhoeven wrote:
> Add and helper macro for iterating over all DMAC channels, taking into

s/and helper/a helper/

> account the channel mask. Use it where appropriate, to simplify code.
>
> Restore "reverse Christmas tree" order of local variables while adding a
> new variable.
>
> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
> ---
> v2:
> - Put the full loop control of for_each_rcar_dmac_chan() on a single
> line, to improve readability.
> ---
> drivers/dma/sh/rcar-dmac.c | 22 ++++++++++------------
> 1 file changed, 10 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/dma/sh/rcar-dmac.c b/drivers/dma/sh/rcar-dmac.c
> index a57705356e8bb796..537550b4121bbc22 100644
> --- a/drivers/dma/sh/rcar-dmac.c
> +++ b/drivers/dma/sh/rcar-dmac.c
> @@ -209,6 +209,10 @@ struct rcar_dmac {
>
> #define to_rcar_dmac(d) container_of(d, struct rcar_dmac, engine)
>
> +#define for_each_rcar_dmac_chan(i, chan, dmac) \

I would have placed the iterator (chan) after the container being
iterated (dmac), but it seems there are some for_each_* macros doing it
the other way around (they may be older though).

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> + for (i = 0, chan = &(dmac)->channels[0]; i < (dmac)->n_channels; i++, chan++) \
> + if (!((dmac)->channels_mask & BIT(i))) continue; else
> +
> /*
> * struct rcar_dmac_of_data - This driver's OF data
> * @chan_offset_base: DMAC channels base offset
> @@ -817,15 +821,11 @@ static void rcar_dmac_chan_reinit(struct rcar_dmac_chan *chan)
>
> static void rcar_dmac_stop_all_chan(struct rcar_dmac *dmac)
> {
> + struct rcar_dmac_chan *chan;
> unsigned int i;
>
> /* Stop all channels. */
> - for (i = 0; i < dmac->n_channels; ++i) {
> - struct rcar_dmac_chan *chan = &dmac->channels[i];
> -
> - if (!(dmac->channels_mask & BIT(i)))
> - continue;
> -
> + for_each_rcar_dmac_chan(i, chan, dmac) {
> /* Stop and reinitialize the channel. */
> spin_lock_irq(&chan->lock);
> rcar_dmac_chan_halt(chan);
> @@ -1828,9 +1828,10 @@ static int rcar_dmac_probe(struct platform_device *pdev)
> DMA_SLAVE_BUSWIDTH_2_BYTES | DMA_SLAVE_BUSWIDTH_4_BYTES |
> DMA_SLAVE_BUSWIDTH_8_BYTES | DMA_SLAVE_BUSWIDTH_16_BYTES |
> DMA_SLAVE_BUSWIDTH_32_BYTES | DMA_SLAVE_BUSWIDTH_64_BYTES;
> + const struct rcar_dmac_of_data *data;
> + struct rcar_dmac_chan *chan;
> struct dma_device *engine;
> struct rcar_dmac *dmac;
> - const struct rcar_dmac_of_data *data;
> unsigned int i;
> int ret;
>
> @@ -1916,11 +1917,8 @@ static int rcar_dmac_probe(struct platform_device *pdev)
>
> INIT_LIST_HEAD(&engine->channels);
>
> - for (i = 0; i < dmac->n_channels; ++i) {
> - if (!(dmac->channels_mask & BIT(i)))
> - continue;
> -
> - ret = rcar_dmac_chan_probe(dmac, &dmac->channels[i], data, i);
> + for_each_rcar_dmac_chan(i, chan, dmac) {
> + ret = rcar_dmac_chan_probe(dmac, chan, data, i);
> if (ret < 0)
> goto error;
> }

--
Regards,

Laurent Pinchart